Development Of An Angle Encoder Calibration Device For High And Low Temperature Environments

With the rapid development of China’s aerospace industry,more and more complex and precise institutions need to perform a variety of performance tests and reliability assessments in the extreme environment such as space vacuum,high and low temperature on the ground.In this project,the precision performance tester of the precision mechanism developed by the project cooperation unit uses the angle encoder to measure the angular displacement of the space mechanism.At present,the angle source value trace method in high and low temperature environment is still blank.They can only be calibrated at room temperature.In this paper,the angle encoder calibration technology in high and low temperature environment is studied,mainly including the following contents:(1)The overall program and traceability method research.According to the technical indicators,the overall scheme design of the high-low temperature environment angle encoder calibration device is realized,and the value traceability system suitable for the high-low temperature environment angle encoder calibration device is established.(2)Device design.According to the requirements of mechanics and precision,the mechanical support structure of the inner and outer parts of the high and low temperature chamber and the design of the shafting structure are designed,and the selection of each component is completed.The servo motor is used as the driving force source of the calibration device and is collected by NI data.The system and highprecision standard angle encoder realize the measurement of the angular displacement of the drive shaft;complete the preparation of the measurement and control software of the upper computer.(3)Error analysis.The error source of the calibration device is analyzed,and four error sources that affect the calibration result are obtained: standard error,installation eccentricity error,torsion angle error,angular misalignment error,and theoretical analysis,wherein the transmission shaft is affected by temperature.The angular error is simulated by COMSOL Multiphysics software to verify the correctness of the theoretical analysis.The linear regression model is used to compensate the torsion angle error of the drive shaft affected by temperature.(4)Experimental design and uncertainty assessment.The calibration experiment of the high and low temperature environment angle encoder calibration device is carried out by standard instruments such as angle measuring turret,multi-face prism,self-collimator,etc.,and the measurement uncertainty evaluation of the high-low temperature environment angle encoder calibration device is completed,and the calibration device is not expanded.The degree of certainty is 8.82",which meets the requirements of the preset technical specifications,and can calibrate the angle encoder in high and low temperature environment.The maximum absolute error of the angle encoder at-20 °C is-31.78",at 100 °C The maximum absolute error is 37.80".